Stoker feed mechanism



Nov. 26, 1946.

c. BARR STOKER FEED MECHANISM 7 Original Filed Sept. 17. 1940 4 Sheets-Sheet 1 v N m M INYENTOR 62% Q. @m

M. AW

ATTORNEY WITNESSES? Nov. 26,1946. R

swomm FEED mncmmxsu Original Filed Sept. 17, 1940 4 Sheets-Sheet 2 INVENTOR A MR aw BY b QM Q 9o 90 ATTORNEY Nov. 26, 1946.

C. R. BARR STOKER FEED MECHANISM Original Filed Sept. 17. 1940 4 Sheets-Sheet 3 W11 D ID HW HWW NIHVI/ N J l i m mq fi INVENTOR WITNESSES:

BY @A I ATTORNEY Nov. 26, 1946. c, R, ARR I 2,411,703

7 STOKER FEED MECHANISM Original Filed Sept. 17, '1940 4 Sheets-Sheet 4 Jim/ a W ITNESSES: J INVENTOR ATTORNEY Patented Nov. 26, 1946 i I iilTED- STATES. PATEN T OFFICE 1 s'ronsn FEED MECHANISM Charles R. Barr, Bellevue, rs.

Original application September 1'7, 1940. Serial No. 357,127. Divided'and this application September 23, 1944, Serial No. 555,452

1 p This invention relates to new and usefuli'improvements in 'stokers and the present application is a division of an application-serially numbered 357,127, filedSeptember 17, 1940, which has matured as United States Patent No. 2,359,742, granted October 10, 1944. It is among the-objects of. this invention to'provide a stoker adapted for feeding a, proper quantity of. coal properly distributed over the fire bed at a proper time to ob-.

tain maximum efliciency of combustion throughout the fire box area. The invention will become more apparent fro a consideration of the accompanying drawings constituting a part hereof in which like reference characters designat like parts and in which Fig. l is a rear elevational view of a stoker feed 1 apparatus embodying the principles of this invention;

Fig. 2 a side elevational view thereof; Fig. 3 a rear elevational view of the mainframe 7 structure for supporting and housing the feed mechanism;

Fig. 4 a side elevational view of the stoker frame;

Fig. 5 a horizontal cross-section partially in I elevation taken along the line 55, Fig. 4;

5' Claims. (01. 110 108) paddles I mounted on a square drive shaft 1,

the paddle conveyor being constructed in sections, as shown in Fig. l, with successive sections staggered, as shown in Fig. '7. The shaft I, is driven by a pawl and ratchet mechanism, Figs. 2 and 11. The shaft 1 is keyed at 8 and 9, Fig. 11, to a pair of conically shaped friction disks I0 and 'H which coact with a ratchet wheel I! having teeth is that are engaged by a pawl I4, the contact between the friction disks i0 and ll .and the ratchet wheel i2 being adjusted by means of the nut I5 on the end of shaft 1.

Suitable clearance i6 is provided between the conical disks and the ratchet wheel to assure contact of the conical surfaces of the engagingmembers. The purpose of the friction drive is to avoid damage to the feed mechanism, particularly the paddle conveyor 6 if a large piece Fig. 6 a top plan [view diagrammatically illus- I trating the directional path of the fuel as distributed by the stoker feed mechanism; Fig. '7 a vertical cross-section partially in ele vation of a fire box and the stoker mechanism;

Fig. 8 a top plan view of an adjustable crank; Fig. 9 a vertical section thereof taken [along the Fig. 10 a vertical section partially inelevation of slate or other foreign element such as iron bars or spikes are .fed from the hopper to the paddle conveyor. If, for example, an iron bar would become lodged in the paddle conveyor, the feed mechanism, including the ratchet drive, would continue to operate without revolving the conveyor shaft 1. To dislodge the obstruction,

pawl 14 is disengaged and shaft 1 shaken back and forth by means of lever Ia.

- As shown in Figs. 2 and 11, pawl I4 is pivotaliy mounted on a crank I! that is pivoted on the drive shaft 1. The crank i1 is connectedby a link 18 to a lever l9 that is pivoted at 20, the

other end of thelever being connected at?! to of the crank ofFlg. 8 taken along the lines I ll-h Fig. 8: and

Fig. 11 a cross section of the friction feed drive taken along the line i l-i I, Fig. 2.

With reference to Figs. 6 and 7 of the drawings, it is the primary object of the stoker feed mechanism to distribute the coal or coke over the fire bed uniformly throughout the length and breadth thereof, the arrows in Fig. 6 illustrating the path of the coal as it leaves the stoker, which may be generally designated by the numeral i.

Fig. '7 demonstrates the horizontal path of the coal as it leaves the spreader apron 2 of the stoker,

the numeral 3 designating an evenly distributed bed of coal on a stationary grate or hearth t. The distribution of the coal over the fire bed, as

shown in Figs, 6 and 7, is eifected by means of the following mechanism.

The coal is placed in a hopper 5, Fig, 7, and

a link-22,0116 end of Which is mounted on an adjustable crank pin 28. Crank pin-23 is driven by shaft 24 that is coupled to a variable speed transmission generally designated by the reference chsracterEB, and which may be of the type employed in automotive vehicles having a shifting lever 28, as shown in Fig. 1. Transmission 25 is coupled to a gear reduction mechanism generally designated by the numeral 21 that is driven is fed by gravity mm the path of a plurality of a by an electric motor 28 or any other suitable prime mover.

It'is to be noted with reference to Fig. 1 that the stoker frame may be constructed of a one- U i briefly as follows:

the charging opening of the furnace, as shown -mounted on the transmission shaft 24 to rotate 'the drive disk 28 to, vary the thrust in accordance with the desired rate of feeding through the pawl and ratchet mechanism. To effect the adjustment, it is necessary to remove the clamping plates 32, remove the crank pin 28 from the slots st and place it in its adjusted position. The clamp plates 32 are then inserted in the slots of pin 23, as shown in Fig. 9. and the crank'pin is held against movement by the interacting teeth of the pin and drive disk. It is apparent that a wide range of feed adjustment is provided through the transmission 25 and the adjustable crank pin to obtain any desired rate of feeding the fuel to the fire box.

Distribution of the coal after it is delivered'by the paddle conveyor 6 to the spreader apron is I effected by a plurality of blast nozzles 35, Fig. 7,

one end of which communicates with a steam box 38 and the other end with flared grooves 31 of the apron 2, Fig. 5. The steam or blast emitted by the severalnozzles may be separately regulated by a needle valve is having a stem extending through a strap 38, each valve stem being provided with a grip dd to effect adjustment of the blast emitted from the nozzles 55. The sides of the apron 2 are'provided with flaring blades ti to permit distribution of the fuel at the front end of the fire box. Steam or compressed air is supplied to the chamber 33 through a conduit l2, and one end of the chamber is plugged at 43. The nozzles 35 may be adjusted to distribute the fuel over any size fire box and the pressure regulated to distribute the fuel throughout the length of the fire box. I

The operation of the stoker feed mechanism The stoker is clamped to in Fig. 7, and the hopper S is charged with coal which, because of the emcient combustion obtained by the distribution of the fuel in the fire box, may be of an inferior grade. Motor 28 is thenenergized and the shifting lever 28 is moved to the desired speed position. Power is transmitted through transmission 23 to the shaft 24 to rotate the drive disk 28 which revolves to actuate crank pin 23 which has been set on the drive disk 28 to exert a predetermined angular thrust on lever it through the connecting link 22. As the lever is oscillates, the pawl housing is subjected to oscillating movement which in one direction causes pawl It to engage the teeth of ratchet wheel 62, which in turn rotates the square shaft i of the paddle conveyor 8. As the conveyor 6 revolves, coal is fed to the apron 2 in the path of the steam jets ll! and is lifted from the apron and distributed over the fire box area, as shown in-Flgs. 8 and. 7. By proper adjustment of the needle valve 3'8,'the necessary amount of blast is obtained to provide for a uni-'- form distribution of coal over the entire hearth of the fire box to an even thickness to produce, most efficient combustion; both as to time of feeding and intensity of heat. The wide range of ad- Justment of the feed mechanism adapts the invention to the use of steam boilersof all isizes 4 and capacity and also gives to each individual boiler is wide capacity range.

The use of the speed transmission 25 coupled with'the feed adjustment of the panel conveyor permits rapid change of the rate of fuel feed in accordance with the needs of the boiler, for example, if the boiler is rated 100 H. P. and the fuel consumption is 8 pounds per H. P. per hour, the adjustable crank 23 may be set to feed 800 pounds of coal per hour with the transmission 25 set for normal feeding speed. By shifting lever 26 to either increase or decrease the transmission speed, the fuel feed may be correspondingly increased. or decreased to get double or half the coal feed capacity to meet any particular operating requirements.

The apparatus is durable and compact and takes up very little space at the charging end of the furnace.

Because of the even thickness of the fuel bed, it is possible with proper aeration of the grate to burn slack or the waste product of coal mines without the formation of clinkers.

Although one embodiment of the invention has been herein illustrated and described, it will be evident to those. skilled in the art that various modifications may be made in the details of construction without departing from the principles herein set forth.

30 I claim:

1. In a stoker feed mechanism, fuel feeding means comprising a feed wheel having groups of blades in angular and axially spaced relation staggered so that when rotated only one blade of the entire feed wheel isoperative to deliver an increment of fuel to a predetermined space of the feeding station, whereby successive charges are delivered from one end entirely across to the other end of said wheel, a drive mechanism for said feeding wheel including a-shaft, a. plurality of friction members mounted on said shaft, a drive wheel in frictional engagementtherewith, said wheel having teeth for engagement by a pawl, a bracket mounted for angular movement on said drive having a pawl for engaging the teeth of the drive wheel and having a lever, one end of which is connected to a crank pin, a driving crank for said crank pin having adjusting means for varying the thrust of said crank pin, and a prime mover for rotating said crank head whereby said feed wheel is subjected to intermittent angular movement.

2. In. a stoker feed mechanism, fuel feeding means comprising a feed conveyor having fuel impelllng faces in angular and axially spaced relation. which when rotated deliver a unit increment of fuel successively to different areas of the feeding station, a drive mechanism for said feeding conveyor including a shaft. a plurality of friction to members mounted on said shaft, a drive wheel in frictional engagement therewith, said wheel having teeth for engagement by a pawl, a bracket mounted for angular movement on said drive having apawl for engaging the teeth of the drive 66 wheel and having a lever, one end of which is the thrust of said crank pin, said crank head having a T-slot with teeth at the bottom of the slot, 70 andsaid crank pin having'a T-head with teeth interacting with the teeth of said crank head to be adjustable radially to vary the stroke of said ratchet, actuating lever, and a prime mover for rotating said crank head. 7s 3. In. a stoker feed mechanism, a conveyor for connected to a crank pin, a driving crank for saidcrank pin having adjusting means for varying:

v 5 feeding solid fuel having fueiimpelling faces .in angularly and axially spaced relation which when rotated feeds relatively small unit increments of fuel to a fuel receiving station, a drive shaft for said conveyor having a friction drive mounted on one end thereof, a ratchet wheel for actuating 1 advance the feed" wheel for feeding fuel and to permit continuing rotation of the drive mecha' nism if the feed wheeiis obstructed against rotarymovement. v for feeding solid 4. ma stoker mechanism fuel to a fire box, afeed wheel having a pluralpawl-toangular mov ementjnand a crank shaft fcractuatingsaidlevex-Jhecrankofsaidshaft ity of mulariy and axially spaced blades which when rotated successively feed a measured unit increment of fuel from one enduo'f the feed wheel a entirely across to the other end of said wheel, drive mechanism including a shaft for said wheel; a friction drive on the end of the shaft comprising a plurality of'conical membera-a ratchet wheel mounted on said conical members. in 'fricgs movement.

tional engagement therewith, a pawl engaging the iettlne 88 d pawl to oscillatory movement to in- 1 teeth of said ratchet, a lever for subjecting the i being adjustable to vary the arc of movement of the pawl actuating lever, and a prime mover ineluding, avariable speed transmission for said crankshaft, whereby the volume -of fuel delivered by said feed wheel per unit of time may be varied while maintaining constant the unit quantity de- 'livered by'each blade -in its fuel feeding function.

. 5. In a stoker feed mechanism, a conveyor for feeding solid fuel having fuel impelling faces which when rotated deliver a unit increment of fuel successively to different areas of a feedin station, said conveyor being mounted on a shaft having its axis'dlsposod in a horizontal plane. a friction drive for said shaft comprising a pinrality of conical disks mounted for rotation with said shaft, a drive member having complementary faces the conical surfaces of said disk and having ratchet teeth thereon, a ratchet pawl for ensuing said teeth, and a crank arm for subtermittentiy advance said friction drive disk to subiect the fuel conveyor .to intermittent rotary ensues a. name. 

